Non-Porous Thermoformable Polyurethane Solid

ABSTRACT

The subject disclosure presents systems and methods for manufacturing a non-porous thermoformable polyurethane solid by combining an uncured polyurethane resin with Aluminum Trihydrate (ATH), a plurality of particulates, molecular sieves, and color particulates. This combination is mixed in a vacuum for a time period sufficient to initiate an exothermic reaction within the mixture. After the time period, the exothermically reacting mixture is allowed to cure to form the polyurethane solid. The curing may occur in a mold, i.e. by pouring or injecting the mixture into the mold. Alternatively, the mixture may be sprayed on to a surface and allowed to cure.

This application is a continuation of U.S. patent application Ser. No.14/321,760, filed Jul. 1, 2014, now U.S. Pat. No. 9,469,744; which is acontinuation of U.S. patent application Ser. No. 13/101,410, filed May5, 2011, now U.S. Pat. No. 8,765,871; the contents of which are herebyincorporated by reference herein in their entirety into this disclosure.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to forming polyurethanes. Morespecifically the present invention relates to forming a medium-to-highdurometer, non-porous, and thermoformable polyurethane usingbio-renewable and recycled ingredients.

Background of the Invention

The state of the art for constructing surfaces such as bars,countertops, etc., has, for decades, involved acrylics. From the timethat DUPONT developed their acrylic-based CORIAN material until today,acrylics and acrylic/polyester blends have been in dominant use for suchapplications. The benefits of such composite materials are numerous:acrylic/polyester countertops integrate well with other surfaces andstructures without forming lips or seams when fabricated, and arenon-porous, therefore being suitable for sterile applications such ashospitals.

However, several major limitations exist for these materials.Specifically, they are extremely brittle, crack and scratch very easily,and are fairly expensive and heavy. It takes a substantial amount oflabor to transport these products to their desired locations, whiletheir brittleness only adds to the overall costs of using them asinterior surfaces.

Another popular composite solid uses a polyurethane resin as its base.Polyurethane is typically manufactured with two groups of at leastbifunctional substances as reactants: compounds with isocyanate groups,and compounds with active hydrogen atoms. The physical and chemicalcharacter, structure, and molecular size of these compounds influencethe polymerization reaction, as well as ease of processing and finalphysical properties of the finished polyurethane. In addition, additivessuch as catalysts, surfactants, blowing agents, cross linkers, flameretardants, light stabilizers, anti-settling agents, and fillers areused to control and modify the reaction process and performancecharacteristics of the polymer.

However, existing polyurethanes are extremely susceptible to water.Specifically, any moisture content influences the reaction and createsbubbles of CO₂ gas. This results in foaming within the material, makingit porous. The porosity automatically disqualifies a polyurethane frombeing used in sterile applications as well as kitchen countertops,sinks, etc.

The use of polyols derived from vegetable oils to make polyurethaneproducts began attracting attention around 2004. The rising costs ofpetrochemical feedstocks and an enhanced public desire forenvironmentally friendly green products have created a demand for thesematerials. Memory foam mattresses and spray-on polyurethane foaminsulation for buildings are becoming increasingly common. The FordMotor Company recently announced its intentions to use polyurethane foammade using natural oil polyols in the seats of its Ford Mustang.However, much of the development being performed on the use ofnatural-oil polyurethane products is limited to, for example, seats,headrests, armrests, soundproofing, and body panels. In other words,these applications make use of the foaming properties of polyurethane,and do not satisfy the need for a non-porous polyurethane solid. What isneeded is a durable, non-porous, thermoformable, and colorablepolyurethane.

SUMMARY OF THE INVENTION

The subject disclosure addresses the above-identified problems in theconventional art by combining an uncured polyurethane resin with AluminaTrihydrate (ATH), particulate glass, molecular sieves, and colorparticulates, along with anti-settling agents such as fumed silicas.Mixed under a vacuum, the resultant mixture exothermically reacts in amold and is cured. The cured polyurethane is a medium-to-high durometer,impact-resistant, fire-retardant, thermoformable, and non-porous solid.This makes the inventive solid applicable to a variety of applicationssuch as countertops, bathtubs, sinks, etc. In exemplary embodiments, theusage of natural oil polyols, such as soy polyols, as well as recycledparticulate glass, ensures that the raw materials that are used tomanufacture the inventive polyurethane solid come from renewable andenvironmentally friendly sources.

In one exemplary embodiment, the present invention is a thermoformablenon-porous polyurethane material including a plurality of isocyanates, aplurality of polyols, alumina trihydrate (ATH), particulate glass, aplurality of molecular sieves, and fumed silica. These ingredients arecombined and mixed in a vacuum mixer for a duration and at a vacuumlevel sufficient to induce an exothermic polymerization reaction. Theexothermically reacting mixture is formed into a composite materialafter said duration of mixing. The plurality of isocyanates and theplurality of polyols together constitute between 20-70% of a totalcontent of the mixture, the ATH constitutes between 15-30% of the totalcontent of the mixture, the particulate glass, or other particulates,constitute between 5-50% of the total content of the mixture, and theplurality of molecular sieves constitutes between 2-10% of the totalcontent of the mixture. A plurality of color particulates may be addedfor color. The anti-settling or thickening agent, such as fumed silica,is added to constitute 0.1%-10% of the mixture. The mixture is formedinto the composite material by pouring or injecting into a mold andallowing curing.

In another exemplary embodiment, the present invention is a method formanufacturing a thermoformable non-porous polyurethane material,including combining a plurality of isocyanates, a plurality of polyols,alumina tri-hydrate, particulate glass, a plurality of molecular sieves,and fumed silica to form a mixture, mixing the mixture under a vacuum,wherein the mixing occurs for a time period sufficient to create anexothermically reacting mixture, and forming a composite material usingthe exothermically reacting mixture by curing the exothermicallyreacting mixture for a curing period. The composite material may beformed by pouring the exothermically reacting mixture into a mold,injecting the exothermically reacting mixture into a mold, or sprayingthe exothermically reacting mixture on to a surface. The vacuum level ismaintained at 15-20 inches of mercury, while a temperature of theexothermically reacting mixture is maintained at no greater than 10degrees F. above an ambient temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a system for manufacturing a polyurethane solid, accordingto an exemplary embodiment of the present invention.

FIG. 2 shows a method for manufacturing a polyurethane solid, accordingto an exemplary embodiment of the present invention.

FIG. 3 shows another method for manufacturing a polyurethane solid,according to another exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description presents exemplary embodiments of thepresent invention, including systems and methods for manufacturing athermoformable polyurethane solid by combining an uncured polyurethaneresin with Alumina Trihydrate (ATH), cast particulates, molecularsieves, and color particulates. This combination is mixed in a vacuumfor a time period sufficient to initiate an exothermic reaction withinthe mixture. After the time period, the exothermically reacting mixtureis allowed to cure to form the polyurethane solid. The curing may occurin a mold, e.g., by pouring or injecting the mixture into the mold.Alternatively, the mixture may be sprayed on to a surface and allowed tocure.

Generally, the resin includes a mixture of a plurality of isocyanatesand a plurality of polyols, the resin constituting between 20% and 70%of the total contents of the mixture. ATH is pure or pre-mixed with asmall percentage of color particulates, and constitutes between 15% and30% of the total contents of the mixture. Finely ground/powdered castparticulates constitute between 5% and 50% of the total contents of themixture, and may include recycled powdered glass. A plurality ofmolecular sieves, such as 3A or 4A molecular sieves, is used to adsorbwater molecules from the mixture, and constitutes between 2% and 10% ofthe total contents of the mixture. Pigments, or color particulates,constitute between 1% and 15% of the total contents of the mixture. Insome embodiments, a combination of molecular sieves and colorparticulates constitutes approximately 5% of the total contents of themixture. Fumed silica or other anti-settling or thickening agentsconstitute 0.1%-10% of the mixture to retard separation and settling ofthe particulate fillers. Finally, up to 8% of the total contents of themixture may include a UV stabilizer.

The resulting polyurethane solid is medium-to-high durometer (hardness),impact-resistant, fire-retardant, thermoformable, and non-porous. Thismakes the polyurethane solid desirable for a variety of applicationssuch as countertops, bathtubs, sinks, etc. In some exemplaryembodiments, the amount of particulates such as powdered glass may beincreased to up to 70% of the total contents of the mixture, resultingin a harder quartz-like solid having several additional applications,such as extremely stain and scratch resistant table and cabinet tops.This resultant is also very chemical resistant, making it useful forlaboratory furniture and table tops. Further, the usage of natural oilpolyols, such as soy polyols as well as recycled particulate glassensures that the raw materials that are used to manufacture thispolyurethane solid come from renewable and environmentally friendlysources.

A “resin”, as used herein and throughout this disclosure, is acombination of a plurality of polyols and a plurality of isocyanatesthat may be packaged and sold together, but are kept separate until theprocess begins. The resin may be customized for the application, withthe properties of the resulting mixture having a viscosity and a geltime that are adjusted using one or more catalysts. In one exemplaryembodiment, the mixture uses a resin comprising 46% (±4%) soy polyol and54% (±4%) Methylene Diphenyl Diisocyanate (MDI), with the resultingresin having a viscosity of 900 centipoise, and a gel time of 28-30minutes. Such a combination is commercially available, for instance,from the Urethane Soy Systems Company.

A “polyol”, as used herein and throughout this disclosure, is a compoundwith multiple hydroxyl functional groups available for organicreactions. Polymeric polyols are mainly used as reactants to make otherpolymers, and may react with isocyanates to make polyurethanes. Somevegetable oils, such as soybean oil, peanut oil, and canola oil, containcarbon-carbon double bonds, but no hydroxyl groups. There are severalprocesses used to introduce hydroxyl groups onto the carbon chain of thefatty acids, and most of these involve oxidation of the C—C double bond.The vegetable oils may further be treated with ozone. In one exemplaryembodiment, the present invention uses a soy polyol, thereby ensuring abio-renewable raw material.

An isocyanate includes any organic compound containing an isocyanategroup, i.e. the functional group of atoms N═C═O (1 nitrogen, 1 carbon, 1oxygen). An isocyanate may have more than one isocyanate group. Forinstance, an isocyanate that has two isocyanate groups is known as adiisocyanate. Diisocyanates such as MDI are generally manufactured forreaction with polyols in the production of polyurethanes.

Alumina tri-hydrate (ATH), or hydrated alumina, is a non-toxic,non-corrosive, flame-retardant, and smoke suppressant material utilizedin elastomeric applications. ATH is a relatively hard filler andincludes chemically bound water that is released at high temperatures.Consequently, ATH is frequently used as a fire retardant material. Inother words, materials including ATH are self-extinguishing if ignited.In one exemplary embodiment, the present invention uses a combination ofATH with color particulates.

Fumed silica consists of microscopic droplets of amorphous silica fusedinto branched, chainlike, three-dimensional secondary particles whichthen agglomerate into tertiary particles. The resulting powder has anextremely low bulk density and high surface area. Its three-dimensionalstructure results in viscosity-increasing, thixotropic behavior whenused as a thickener or reinforcing filler.

FIG. 1 shows the manufacture of a thermoformable polyurethane solid,according to an exemplary embodiment of the present invention. The rawmaterials, e.g., isocyanates 101, polyols 102, ATH 103, particulateglass 105, molecular sieves 107, and color particulates 109, are allweighed as per the proportional percentages described herein and addedat the same time to a vacuum chamber 121 of a vacuum mixer 120. After10-15 minutes of mixing under vacuum, fumed silica 108 is added to themix, and the vacuum mixer continues mixing for another 1-3 minutes.Vacuum mixer 120 includes at least a mixing lid 122, a pressure gauge125, a temperature gauge 126, and a stirring portion 128. The sensorsfor measuring temperature and pressure (not shown) may be attached tostirring portion 128 coupled to mixing lid 122, with wires sendingsignals back to gauges 125, 126. Further, although a standard vacuummixer is shown, any other type of vacuum mixer may be used as is knownin the art. The only requirement is that the vacuum mixer is able to mixmixture 110 for a duration sufficient to induce an exothermic reactionwithin mixture 110, generally no longer than 18 minutes.

Arrow 130 shows the mixing process for this exemplary embodiment.Mixture 110 is mixed for approximately 10-15 minutes, a range of timeexperimentally shown to be ideal for the above listed proportions ofingredients. Then the fumed silica is added, and the mixture is mixedfor another 1-3 minutes. Throughout the mixing time, the vacuum chamber121 is maintained at between 15 and 20 inches of mercury, orapproximately 0.5-0.6 atmospheres. Further, the environment external tovacuum mixer 120 is either maintained at room temperature or adjusted soas to maintain an internal temperature of no greater than 10 degrees F.over the ambient temperature. For the purposes of this disclosure, anambient or room temperature ranges between 70° F. and 80° F. In otherwords, the pressure and temperature inside vacuum chamber 121 isadjusted so that the exothermically reacting mixture 110 does not reachan excessive temperature. Under high temperatures and low pressures, theexothermically reacting mixture 110 may begin to boil. This is expected;however, the temperature should not exceed 10 degrees F. over theambient temperature, which is generally between 70° F. and 80° F.

After the 16-18 minute period has passed, mixture 110 is sufficientlymixed and the exothermic reaction is occurring uniformly throughoutmixture 110. At this point, vacuum mixer 120 is shut down, the vacuumreleased from vacuum chamber 121, and exothermically reacting mixture110 is poured into a mold 140. The exothermically reacting mixture 110is poured evenly into mold 140 to avoid air entrapment. An additionalperiod of time, or a curing period, enables the exothermically reactingmixture 110 to cure to form a polyurethane solid. Mold 140 is shown tobe a flat mold ideal for creating a polyurethane sheet. However, mold140 may be any other shape such as that of a sink, bathtub, or anyconceivable shape requiring a non-porous polyurethane solid, such as theone manufactured by the inventive system.

In certain exemplary embodiments of the present invention, each of thematerials may be added one at a time to a container such as a blendingkettle, and stirred with a mixing paddle without removing from the scaleto roughly blend the mixture. This rough blending ensures that fillersare not allowed to stay “caked” to the bottom, and are uniformlydistributed throughout the mixture. The blending kettle may then besealed, applied under vacuum, and vacuum mixed using any appropriateblending platform. The kettle would then be moved by a gantry to theprepared mold.

FIG. 2 shows a method for manufacturing a thermoformable polyurethanesolid, according to an exemplary embodiment of the present invention.The method begins 231 by preparing the raw materials required to formthe polyurethane. In this embodiment, raw materials for the resin areprepared 232 in one of several ways. For instance, a plurality ofpolyols and a plurality of isocyanates are measured out by weight andpoured into a container, or a chamber of a vacuum mixer. Then, beforethe plurality of polyols and iscocyanates is mixed, the additionalingredients, including the molecular sieves, ATH and/or DURASTONEparticulates, color particulates, particulate glass, UV stabilizers, andany desired special effects particulates, are measured out by weight andadded 233. Preparation of the ingredients may take a short amount oftime, such as 10 minutes, or may take longer. However, to ensure auniform exothermic reaction prior to curing, the time to combine all theingredients should be minimized.

The combined ingredients are then poured into a vacuum mixer, and thevacuum mixer is started 234. The contents are mixed for about 10-15minutes, and then the fumed silica is added 235. The contents continueto mix under a vacuum 236 of 15-20 inches of mercury until an exothermicreaction begins 237. If the exothermic reaction has not yet started,then the mixing 236 continues until the entire mixture is exothermicallyreacting. This decision may be performed, for instance, by monitoring atemperature of the contents of the vacuum chamber or the mixture usingthe apparatus shown above with respect to FIG. 1. When a desiredtemperature is reached, which should take an additional 1-3 minutesbased on experimental results, the mixture is uniformly undergoing anexothermic reaction. At this point, the vacuum mixer is powered down andthe exothermically reacting mixture is poured or injected into a mold238.

It is very helpful to maintain the vacuum level at approximately 15-20inches of mercury, because higher levels may cause the exothermicallyreacting mixture to boil, while lower levels do not remove enough air,and the resulting polyurethane solid may be porous due to formation ofair holes. In addition, it is also important to keep the externalenvironment as dry as possible, so as to prevent any ambient moisturereacting with the mixture to form a porous solid. Another importantfactor is the timing of the process. Generally, from making firstcontact, polyols and isocyanates begin to exothermically react inapproximately 25 minutes, depending on several factors. The presentinvention accounts for this by setting aside approximately 10-12 minutesfor measuring out and combining all the ingredients, and approximately15-18 minutes for mixing under vacuum. This ensures that at the time ofpouring/injecting into the mold, the mixture is uniformly exothermicallyreacting. A final crucial factor is the temperature of the process. Asdescribed above, higher temperatures cause boiling of the exothermicallyreacting mixture while under vacuum. Consequently, the present inventivemethod prescribes that the ambient temperature be as close to roomtemperature as possible. It is further ideal for the ambient temperatureto be maintained above at least 60 degrees F. Further, externallyheating the mixture may provide for a quicker curing time, but does notaffect the quality of the finished product in any substantial way. Forinstance, the cast solid may be left to cure at ambient temperature, orthe curing may be accelerated by placing in an oven, either for curingor for post-curing. The temperature of the oven should not exceed 150 F.

In one exemplary embodiment of the present invention, the 20-70%polyurethane blend of polyols and isocyanates is commercially availablefrom the URETHANE SOY SYSTEMS COMPANY. In this embodiment, the molecularsieves of 3 or 4 Angstroms are part of the MOLSIV ADSORBENTScommercially available from UOP, LLC. The 15-30% ATH blend iscommercially available from SAMCO. The 1-15% pigments may be organicpigments, or may include metallic oxides, both of which are availablefrom THE SHEPHERD COLOR COMPANY. 5-30% of glass particulates includerecycled powdered glass, commercially available from REFLECTIVERECYCLING of Texas. The glass particulates may also include the finestmesh of BRITE BLAST abrasive mix available from ABRASIVE WAREHOUSE &EQUIPMENT, also from Texas. The glass particulates are also availablefrom the SURFACE FINISHING COMPANY in Fairfax, Kans. The up-to-8% of UVstabilizer may be the LOWILITE UV B1211 product, available fromCHEMTURA. The mixture may also include different cast particulates fordifferent effects, such as granite or quartz effects available fromARIZONA STONE. The special effects particulates may be added as analternative to or in addition to the glass particulates. The resultingsurface of the cast urethane parts as described above mimics the finishon the mold. I.e. the finish may be textured, or smooth (reflective).Further, the resulting surface may be milled, sanded, and otherwisefinished. The resulting surface has a hardness level of approximately100 on a Type A durometer. Further, the resulting surface is scratch andstain resistant. Finally, depending on the exact percentages of fillerparticulates used, the resulting polyurethane solid ranges in weightfrom 90 lbs to 120 lbs per cubic foot. Fumed silica is added asanti-settling or thickening agent, commercially available as AEROSILSYNTHETIC AMORPHOUS SILICA 200.

Although the general proportions for each ingredient in the mixture areapproximated above, it is to be noted that the proportional amount ofparticulate glass may vary considerably. For instance, while 20% glassprovides a good scratch-resistant finish to the polyurethane solid, upto 65% glass in the mixture results in a quartz-like solid that may becut or shaped using traditional stone-cutting tools. The glass, whichmay be available from a plurality of sources, includes powdered recycledglass as is typically used for sanding purposes, and resembling a whitepowder. Further, as described above, the ATH blend used by the inventivemethod is also used in acrylic formation. However, the present inventivepolyurethane uses the same combination and ends up being superior toacrylics in several ways, i.e., by being lighter, less brittle, moreflexible, and uses bio-renewable and/or recycled ingredients.

FIG. 3 shows a method for manufacturing a thermoformable polyurethanesolid, according to an exemplary embodiment of the present invention.This method differs from FIG. 2 in that this method is adapted to beapplied to a recipe of ingredients that may differ from the onedescribed above. The method begins 331 by preparing the raw materialsrequired to form the polyurethane. In this embodiment, raw materials forthe resin are prepared 332 in one of several ways. For instance, aplurality of polyols and a plurality of isocyanates are measured out byweight and poured into a container, or a chamber of a vacuum mixer.Then, before the plurality of polyols and iscocyanates is mixed, theadditional ingredients, including the molecular sieves, ATH and/orDURASTONE particulates, color particulates, particulate glass, UVstabilizers, and any desired special effects particulates, are measuredout by weight and added 333. The combined ingredients are then pouredinto a vacuum mixer, and the vacuum mixer is started 334. The contentsare mixed thoroughly, and then fumed silica is added 335.

The contents continue to mix 336 under a vacuum until an exothermicreaction begins 337. If the exothermic reaction has not yet started,then the mixing 336 continues until the entire mixture is exothermicallyreacting. This decision may be performed, for instance, by monitoring atemperature of the contents of the vacuum chamber or the mixture usingthe apparatus shown above with respect to FIG. 1. When a desiredtemperature is reached throughout the mixture, the mixture is uniformlyundergoing an exothermic reaction. At this point, the vacuum mixer ispowered down and the exothermically reacting mixture is poured orinjected into a mold 338.

As in the previous embodiment, it is helpful to maintain the vacuumlevel at approximately 15-20 inches of mercury to avoid boiling athigher pressures or formation of formation of air holes at lowertemperatures. Further, although previous embodiments set asideapproximately 10-12 minutes for measuring out and combining all theingredients, and approximately 15-18 minutes for mixing under vacuum,these timings may vary in the present embodiment.

As described above, the exothermically-reacting mixture may be curedwithin a mold, for instance to create polyurethane sheets. However, themixture may also be sprayed onto a surface and allowed to cure on thesurface. Layers of the mixture may be sprayed at timed intervalsallowing for production of solids having varying properties.

Further, the present invention is highly thermoformable. In other words,with application of sufficient heat, a sheet composed of the inventivepolyurethane solid may be manipulated into a desired shape, and cooledto remain in that shape. This is a significant advantage over acrylicproducts, which may only be thermoformed to approximately a ⅞″ diameter.Further, thermoforming the inventive polyurethane solid requires atemperature of approximately 160 degrees F., whereas acrylic requiresheating of approximately 220 degrees F. to be thermoformed. Moreover,the ubiquitous mixture of 80% acrylic and 20% polyester is extremelyhard and therefore not thermoformable. This means that where prior-artsolids have to be molded to the particular application, the inventivepolyurethane solid may be molded into standard or uniform shapes andsubsequently thermoformed into the desired shape.

Other advantages of the present invention include that the inventivepolyurethane solid has the unique advantage of being colored any color,including black, using the appropriate color particulates. Beingsignificantly lighter than acrylics, a single individual may carry asheet or product composed of the inventive polyurethane solid withoutadditional assistance. The hardness level, slight flexibility, andimpact-resistance of the inventive solid prevent it from being damagedeasily. Further, the inventive polyurethane solid can replace existingacrylic/polyester solid surfaces used in universities, dormitory rooms,hotel/motel shower walls, vanities, and even sensitive applications suchas hospitals, owing to its non-porous properties. Colloidal silver andother equivalents may be added to the mixture to provide bactericidaland anti-fungal properties. The mixture may be fluorinated; as suchpolyurethanes contain high percentage of fluorine-carbon bond which isthe strongest bond among all chemical bonds, therefore providingexcellent resistance to UV, acids, alkali, salts, chemicals, solvents,weathering, corrosion, fungi and microbes. Finally, the inventivepolyurethane solid is also naturally flame-retardant because ATH and themolecular sieves release stored water with heat.

The foregoing disclosure of the exemplary embodiments of the subjectdisclosure has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Many variations andmodifications of the embodiments described herein will be apparent toone of ordinary skill in the art in light of the above disclosure. Thescope of the invention is to be defined only by the claims appendedhereto, and by their equivalents.

Further, in describing representative embodiments of the subjectdisclosure, the specification may have presented the method and/orprocess of the subject disclosure as a particular sequence of steps.However, to the extent that the method or process does not rely on theparticular order of steps set forth herein, the method or process shouldnot be limited to the particular sequence of steps described. As one ofordinary skill in the art would appreciate, other sequences of steps maybe possible. Therefore, the particular order of the steps set forth inthe specification should not be construed as limitations on the claims.In addition, the claims directed to the method and/or process of thesubject disclosure should not be limited to the performance of theirsteps in the order written, and one skilled in the art can readilyappreciate that the sequences may be varied and still remain within thespirit and scope of the subject disclosure.

What is claimed is:
 1. A thermoformable, non-porous, polyurethanematerial, comprising: a plurality of isocyanates; a plurality ofpolyols; alumina trihydrate (ATH); a plurality of particulates; and aplurality of molecular sieves; wherein the plurality of isocyanates, theplurality of polyols, the ATH, the plurality of particulates, and theplurality of molecular sieves are mixed in a vacuum mixer to form amixture, wherein a duration of mixing and a vacuum level of the vacuummixer are sufficient to induce an exothermic polymerization reaction,and wherein the mixture is formed into a composite material after saidduration of mixing.